Solid dosage forms such as capsules and tablets are widely used for delivering active ingredients such as drugs to a person or animal in need of treatment. The main advantage of solid dosage forms is that they are readily administered orally which results in a high level of patient compliance. Similarly, solid dosage forms are used to deliver active ingredients such as agrochemicals into biological systems such as plants, soil strata and natural water bodies.
Solid dosage forms can be produced by forming core elements containing an active ingredient. The core elements may be coated with agents such as pharmaceutically acceptable polymers to form pellets wherein the in situ release profile of the active ingredient is modified by the coating. The core elements or pellets may then be filled directly into hard gelatin capsules, or, alternatively combined with suitable binders and other tablet excipients and compressed to form tablets.
The present invention is primarily concerned with compressed solid dosage forms such as tablets. A build up of static charge is a significant problem during tablet formation using the processes just described. The build up of static charge during core element or pellet formation can interfere with handling and processing of the core elements or pellets. For example, it is generally necessary to remove both over and under size pellets by sieving, and a build up of static charge can interfere with the flowability of the core elements or pellets being sieved. It is also important that the flow of core elements or pellets between a hopper containing the core elements or pellets and a tablet press is uniform and predictable and a build up of static charge can interfere with that flow.
To reduce accumulated static charge or prevent or reduce accumulation of static charge during core element and pellet formation talc in powder form has conventionally been admixed with pellets in small concentrations (≦0.5% w/w). Whilst this talc admixing procedure has been found to be very effective in the case of sieving and subsequent capsule filling, it has been found that treating the pellets with talc in this way is unsuitable when the pellets are to be incorporated into tablets because the resulting tablets are too friable.
The present invention provides processes for producing core elements and pellets that can be used to form tablets but which reduce problems associated with a build up of static charge during core element and pellet formation and subsequent processing. The processes of the invention do not adversely affect tablet formation.
Before turning to discuss the present invention, it should be appreciated that the above discussion of documents, acts, materials, devices, articles and the like is included in this specification solely for the purpose of providing a context for the present invention. It is not suggested or represented that any or all of these matters formed part of the prior art base or were common general knowledge in the field relevant to the present invention as it existed in any particular country before the priority date of each claim of this application.